The death of a baby before his or her first birthday is called infant mortality. The infant mortality rate is an estimate of the number of infant deaths for every 1,000 live births. This rate is often used as an indicator to measure the health and well-being of a city, county, state or nation, because factors affecting the health of entire populations can also impact the mortality rate of infants. There are obvious differences in infant mortality by age, race, and ethnicity; for instance, the mortality rate for non-Hispanic black infants is more than twice that of non-Hispanic white infants.For more information: